This application is the national phase under 35 U.S.C. xc2xa7371 of prior PCT International Application No. PCT/EP98/01381 which has an International filing date of Mar. 10, 1998 which designated the United States of America.
The invention relates to an applicator for the application of a single- or multicomponent fluid, particularly of a (single- or multicomponent) tissue glue, and a method for the application of such a fluid by spraying.
In surgery, increased use is made of tissue glues for the most various purposes. Mostly, these tissue adhesives are multicomponent tissue adhesives and normally two-component tissue adhesives which are applied by use of special applicators. Partially, in addition to the tissue glue, also a (medical) gas, e.g. O2, is ejected for atomizing the discharge tissue glued so that the latter can be applied by spraying.
The production costs for tissue glue are not negligible, making it desirable to perform a dosed application of the tissue glue by use of an applicator.
In doing so, the quantity of tissue glue ejected per actuation of the applicator should be the same each time. For reasons of hygiene, it appears reasonable to design the applicator as a disposable article so that the applicator will be provided for single use only.
It is an object of the invention to provide an applicator for applying a single- or multicomponent fluid, particularly at a tissue glue, which can be manufactured at low cost and is particularly designed as a disposable article and which allows the application of an exactly dosed, always constant quantity of fluid with each use.
According to the invention, for solving the above object, there is proposed an applicator comprising
a housing,
at least one supply container for said fluid, adapted to be mounted to said housing, said supply container comprising a discharge opening and having arranged therein a piston for sliding displacement in the direction of said discharge opening,
an energy storage means comprising a hand-operated tensioning lever, pivotally arranged on said housing, which, when moved from a rest position into a pulling position, causes movement of a spring tensioning element by which a spring for storage of mechanical energy, having one end fixed on said housing, can be transferred from a rest position into a tensioned position, and
a moving means for said piston of said supply container, said moving means being coupled to said energy storage means and comprising a drive element coupled to the other end of said spring, said drive element being adapted to be driven, by the stored mechanical energy of said spring during the transfer from the tensioned position into the rest position of said spring, in increments so as to move a press-on element acting on said piston for displacing it in the direction of said discharge opening of said supply container.
The applicator according to the invention is provided with an energy storage means which is suited for storing mechanical energy which will then be used for dispensing a predetermined quantity of fluid. The energy storage means comprises a spring as a mechanical store, which spring can take a rest position and a tensioned position. By means of a tensioning lever pivotally supported particularly on a handle member of the housing of the applicator, the spring can be transferred from its rest position to its tensioned position. In the process, the manually initiated movement of the tensioning lever from the rest position into a pulling position is translated into a movement for transferring the spring from its rest position to its tensioned position. For this purpose, it is suitably provided that a spring tensioning element is arranged between the tensioning lever and the spring for transferring the spring into the tensioned position upon actuation of the tensioning lever.
The energy storage means has a moving means coupled thereto which comprises a movable press-on element acting on a piston of the storage container accommodating the fluid, for thus slidingly displacing the piston in the direction of the discharge opening of the storage container. Through the moving means, the press-on element is moved in increments in the moving direction, while the energy storage means transmitting its stored energy to the drive element each time when the spring moves back from its tensioned position to its rest position.
The invention provides a simple, mechanically operating mechanism allowing the discharge of fluids in doses and at an exact dosage by use of an applicator. For realizing the invention, no electric appliances and the like are required; instead, the applicator operates in a purely mechanical manner, while the energy respectively required for the discharge of fluid is supplied by a spring which is tensioned by hand.
In an advantageous embodiment of the invention, it is provided that the moving means comprises a spindle, secured against axial displacement and supported for rotation on the housing, with the spindle comprising an outer thread in threaded engagement with the inner thread of a through-hole of the press-on element. During a transfer of the spring from its tensioned position into the rest position, the thus initiated movement of the drive element is translated into a rotation of the spindle. This rotation in turn leads to a linear movement of the press-on element which is secured against being rotated along with the spindle and is guided on the housing for linear displacement. The extend of the rotational movement of the spindle caused by each relaxing of the spring and resulting in a step-wise rotation of the spring, is translated into an advance moving step of the press-on element. The extent of the advance step of the press-on element depends, among others, on the pitch of the thread of the spindle and the extend of the rotation of the spindle per relaxation of the spring.
Preferably, the pivoting movement of the tensioning lever is translated into a rotational movement of the spring tensioning element which for this purpose is supported on the housing for rotation about a rotational axis. The spring, having one end attached to the housing, has its other end eccentrically coupled to the spring tensioning element. In the rest position of the spring, the spring tensioning element is in a stable position which hereunder will be referred to as the first dead-center position. When pressing the tensioning lever by hand so that the latter is moved into its pulling position, the spring tensioning element mechanically coupled to the tensioning lever is rotated by slightly more than 180xc2x0 so that the spring tensioning element is moved slightly beyond its metastabile position displaced by 180xc2x0 relative to the first dead-center position (hereunder referred to as the second dead-center position). Both dead-center positions are defined in that the coupling point between the spring and the spring tensioning element are located on a common line extending in the direction of the length of the spring where also the point of the attachment of the spring on the housing is located. By the movement of the spring tensioning element beyond the metastabile dead-center position, the spring tensioning element under the influence of the spring in its tensioning position, performs a rotation by nearly 180xc2x0, and notably automatically so that the spring will then be again in its rest position wherein its spring bias acting on the spring tensioning element is lower than in its tensioned position. This second rotation of the spring tensioning element, extending over nearly 180xc2x0, is used to move the drive element for step-wise advancement of the press-on element.
Suitably, the mechanical coupling of the tensioning lever to the spring tensioning element is provided with a freewheeling function so that the tensioning lever can remain pressed when the spring tensioning element is automatically moved due to the spring force. Such a freewheeling function is suitably realized by a toothing on the spring element which extends slightly beyond 180xc2x0. This toothing meshes with a toothing of the tensioning lever or with a toothed bar moved by the lever along a linear path, with the tooth on both sides being in mutual engagement for the period of the rotational movement induced by the actuation of the tensioning lever, and then being disengaged.
As already mentioned above, the drive element and the spring tensioning element can be arranged as one element which fulfills both the function of the spring tensioning and the function of driving the press-on element. This is preferably realized in that the spring tensioning element and drive element is provided with a first toothing for meshing with a toothing of the spring tensioning lever, and with a second toothing provided to engage the toothing of an end-side pinion arranged on the spindle. While the first toothing of the spring tensioning/drive element cooperates with the spring tensioning element when the latter is manually moved from its rest position into the pulling position, the second toothing meshes with the end-side pinion of the spindle within the second half of the rotation of the spring tensioning/drive element. The positioning of this toothing and the number of teeth thereof determine the extent of the rotational movement by which the spindle moves per relaxation of the spring. Also this provides for a setting of the fluid quantity discharged per actuation of the tensioning lever which is obtained through the design.
If the drive element and the spring tensioning element are not formed as one part, both of them are suitably arranged on a common rotational axis so that the rotation of the spring tensioning element is translated into a rotation of the drive element which in turn is used for the advance movement of the press-on element.
In an advantageous embodiment of the invention, it is further provided that, simultaneously with the discharge of fluid, also a (medical) gas streams out of a gas discharge opening arranged in the immediate vicinity of the fluid discharge opening of the applicator so that the issued gas will atomize the fluid. In this regard, it is of advantage if the gas discharge period during which the gas issues from the gas discharge opening, begins prior to the fluid discharge period. Thus, the gas discharge is already underway when the fluid is discharged from the fluid discharge opening. In this manner, a formation of drops at the beginning of the fluid discharge is prevented.
Further, it is reasonable to take the same measure also around the end of the deposition process or the spray interval. In other words, gas should also be discharged from the gas discharge opening for a period, although a short one, after termination of the discharge of fluid from the gas discharge opening so that fluid drop possibly still attached to the fluid discharge opening can be deposited in sprayed form.
Within the present invention, the above described timing of gas discharge and fluid discharge in an applicator represents an independent thought which can be put to practice also in applicators of a configuration different from the one described above. Thus, this inventive thought is independently placed under protection irrespective of the applicator disclosed within the frame of the invention.
For a controlled discharge of gas in the above described applicator, the applicator is preferably provided with a gas discharge means for the controlled discharging of gas within a gas discharge period correlating with the spring-driven step-wise movement of the drive element or the actuating of the tensioning lever. Here, the gas discharge period begins earlier than the fluid discharge period during which the press-on element acting on the piston is moved. Further, it is suitable if the gas discharge period ends later than the fluid discharge period.
Preferably, the gas discharge means can be controlled by a control element which can be moved along in increments together with the drive element. Thus, the gas discharge means is controlled by the movement of the spring tensioning element and the drive element, respectively, notably indirectly through the control element.
The gas discharge means suitably is a valve arranged in a gas conduit and biased into its closing position. The valve is provided with an actuating element which is acted on by the control element for moving the valve from its closed position to its opened position. Once the control element does not act anymore on the actuating element, the valve will automatically assume its closed position.
The gas conduit having the valve arranged therein is arranged to connect a gas source for pressurized gas to a gas discharge opening. Thus, the conduit portion of the gas conduit between the gas source and the valve will always have pressurized gas therein. The further movement of this pressurized gas will thus be controlled by the valve.
Preferably, the gas supply system of the inventive applicator, comprising the gas discharge means and the gas conduit, is provided with a time-delayed switch-off characteristic, i.e. from the moment that the control element does not act anymore on the actuating element of the valve, gas will nonetheless by discharged from the gas discharge opening for a certain time. On the one hand, this can be realized in that the gas conduit between the valve and the gas discharge opening is provided with a gas storage chamber for the storage of gas. With each opening of the valve, the storage chamber is first filled with gas before gas will be discharged. This leads to a delayed discharge of gas, which, however, can be accounted for by a corresponding shifting of the point of time of the switch-on of the valve, triggered by the movement of the control element, in relation to the discharge of fluid. The advantage of the storage of pressurized gas in the storage chamber between the valve and the gas discharge opening resides in the fact that gas is discharged from the gas discharge opening for a certain period after the switch-off of the valve until the storage chamber has been emptied or its interior pressure is equal to the ambient pressure of the applicator.
A second alternative for terminating the gas discharge with a time delay resides in that the valve is moved in a time-delayed manner controlled by the pressure of the gas into its closed position when the control element does not act anymore on the actuating element of the valve.
With a valve biased into its closed position, the coupling of the control element and the actuating element can then be realized in a simple constructional manner by providing the control element as a cam to be driven by rotation and acting on the actuating element which is realized as a plunger, to thus move the plunger along a linear path against the bias of the valve. The cam is suitably rotated by the spring tensioning element and respectively the drive element of the moving means of the applicator.